Signal chime



Aug. 18, 1942. L. M. ALEXANDER 2293571 SIGNAL CHIME Fld Jan. 8, 1940 2Sheets-Sheet l i z INVENTOR.

W-'v6 f W ATTORNEY Aug. 18, 1942. L. M. ALExA-NDER 2.293.671

SIGNAL CHIME Filed Jan. 8. 1940 2 Sheets-Sheet 2 ATTORNEY5 Patente ug.18, 1942 SIGNAL CHIME Lowell M. Alexander, Cincinnati, Ohio, assig'norto Nu Tone Chimes Inc., New York,v N. Y., a corporation of New YorkApplication January 8.1940, Serial No. 312,869

3 Claims. (Cl. 200-122) p yor tubes placed adjacent resonators foramplifying the sound. In some cases, the solenoids are arranged tooperate between reeds, the

strikers of the solenoid being impelled flrst in thedirection of the onereed and then rebounding under the influence of a spring to strike theother reed to sound a second note. In many instances the lsound from thechimes of this type fail to attract the attention desired and thesignals are unnoticed.

In some of the more expensive chime devices motor driven rotary switcheshave been used, both forrepeat signaling and for sounding a successionof notes of different`tone. However,

the construction of these chimes is quite complex; motor` are requisite,special transformers are required in most instanees and the chimes.

on the whole, have been much too costly to meet the public demand.

The present invention provides chimes which are capable of repeatedlysounding signals at periodic intervals when they are energized through'a push button. For instance, four, five, eight or ten notes may besounded at intervals of fractions of a second. The number of notes andthe length of time elapsing between successive notes may be varied tosuit the conditions desirable in the particular use of the chimes.

A primary objective of the present invention has been to provide asimple but rugged apparatus which can be constructed at low cost andwhich is capable of sounding automatically a succession of signals inresponse to primary manual control through a push' button.

A further object has been to provide a chime device embodying anautomatic controller for I .repeat signaling which is sufllcientlycompact to be incorporated with the sound-producing appai'atus,` inorder that the entire assembly may i tractive appearance.

A further object has been to provide a chime signal capable of Operatingfrom the usual low voltage transformer of. forinstance, six, eight orfourteen volts, and capable of being installed readily in homes andoiiloes by connection to the wire outlets varranged to supply the usualbells or buzzers.

A still further object has been to provide at low cost. chime apparatuswhich is capable of sounding signals automatically at periodic intervalswhen energized initially by the mo- `mentary .depression of a pushbutton.

Briefiy, the chimes of the present invention are energizedrepetitivelyln response to a primary manual control through a pushbutton or the like, through. automatically operating thermoresponsivecontrol elements. These preferably are bimetallic strips which arearranged to cooperate with one another and move or Warp in the samedirection when heated.

For a chime tooperate satisfactorlly it must respond promptlv 'when apush button of the' type conventionally used is operated. Ifa sin-A g'lebmetallic element equipped with a heater is used to cooperate with astationary contact several difflcultles are encountered in obtainingproper operation of the signals. The intensity of heat provided by theheater determines the rapidity with which the bimetallic elementresponds to the operation of a push button. If the heater is adjusted sothat it heats the bimetallic element quickly to pbtain prompt response,then it is impossible to obtain the desired interval of time between thesuccession of signals, and a hammering or chattering effect isproduced.On the other hand, if the size of the heater is reduced so as to obtainthe desired time interval between signals, then there is a long period,for instance, four to six seconds, elapsing before the first signal noteis sounded after. the push button is operated.

The problem has been to obtain a signal which responds promptly to theoperation of a push button andwhich also thereafter continues to sound asuccession of notes at spaced time intervals so long as the push buttoncontinues to be depressed. This desirable result is obtained by usingcooperating bimetallic strips each having a heating element, with theheating elements beinggso adjusted in relation to the bimeta'llic stripswhich they influence and in relation to each other that clrcuit makingcontact is es'- tablished promptly upon the operationof a push button,so that there is an immediatesignal response and that signals aresounded at spaced flcient to operate the sounding unit when all reisistances are in circuit, but is sufllcient to operate the sounding unitwhen the resistance of the circuit is of lesser magntude.

The thermoresponsive elements operate to control the amount oflresistance in the circuit, periodically shunting a portion of it so asto permit to flow a current of sufl'lcient magnitude to operate thesounding unit.

In the preferred structure the bimetallic strips operate contacts which,when in engagement, shunt or`short circuit one of the heating coils. Itis recommended that this latter heater. be of relatively highresistance, in comparison with the other, in order that the devicerespond promptly when the push button is depressed. The contactsnormally may be either spaced apart or be in engagement with oneanother, as desired. In the following specification theyare 'shown anddescribed as being spaced apart when they are in repose. Since thethermoresponsive elements move 'in the same directionthey areself-compensating in respect tochanges in am-l bient temperature.

In but a second or a fraction after the current flows lin the circuit,'the high resistance heater warps its bimetallic element more than w theadjacent one so that the contacts are closed,

heater on the other element heats it and causes it to move away from thefirst and break the contact. This operation restores the firstresistance in circuit and it in turn heats the first element to cause itto move toward the other and reestablish contact for repetition of thecycle.

Thus, the contact on the first bimetallic element moves toward thesecond. and the second then moves away from the first. Or otherwiseexpressed, the one contact is driven to uchase the other which recedesfrom itafter momentary engagement. At each engagement a note i's struck.These relative uchasing" Operations continue, according to onearrangement of the invention; so long as the push button is depresaed,with notes being sounded at intervals' of frac- 'tions of seconds moreor less depending upon the electrical conditions and the' spacing of thecontacts. It is to be noted that neither of the -re- 'sistances by whichthe bimetallic elements are warped is heated or energized continuously,and it is also to be noted that when the heaters are not energized theyare cooling and therefore receding. It ls for this reason that thechasing of one bimetallic element by the-other takes illustratedgeneraliy at and comprises electri-I pressed. The term n`:hasing, asused in the' one moving toward the other when it is heated and thesecond moving away from the first when it is heated, the first thusrelatively chasing the second.

In some instances it is desirable to have chime signals controlled fromseveral different points. for instance, from a front door and from aback door. In vaccordance with the present construction, an individualsolenoid striker is provided to respond to individual switches locatedat the various points of control. The switches are connected in parallelso that one or a plurality of strikers likewise connected may becontrolled from but a single thermocontroller unit. This feature is. ofcourse, very important from a cost standpoint.

These principles upon which the invention is predicated may be utilizedin various modes of construction. A preferred embodiment of theinvention and several illustrative modiflcations are shown in theaccompanying drawings and those skilled in the art readily willcomprehend the other modiflcations to which the invention issusceptible.

In the drawings:

'Figure l is a diagrammatic illustration of the' typical circuit of achime adapted to be operated from two points of control such as a frontdoor and a rear door.

Figure 2 is an illustration showing the striker mechanism for a tubularor gong type chime which may be used in place of thev resonator sounderof Fisur'e 1.

Figure 3 is a modiflcation of the circuit shown in Figure l. v

Figure 4 is a further modiflcation of the circuit shown in Flgure l. y

Figures 5 and .6 are diagrams illustrating the operation of the circuitof Figure 4.

Figure 7 is an illustration of a push button arranged to hold theprimary circuit for auto-7 matic operation of a chime. I

Figure 8 is an illustration of a modified thermocontroller unit.

In'Figure l, the chime sounding mechanism ,is

cally operated Striker units 2, a resonator I. and a reed or chime bar 4placed adJacent the resonator. Each of the Striker units comprises anarmature I which is adapted to be moved magnetically when itssurrounding solenoid coil is ener-V gized electrically. One of thestrikers may be arranged to strike one bar then rebound to strike theother, for sounding double notes. if desirable. The details of theconstruction of these elements form no part of the invention, areA wellknown in the art and further description of them is not believednecessary.

The thermocontroller unit is indicated gen'- erally at 8 and comprisesbimetallic element 'I and. a bimetallic element 8 placed adiacent oneanother and both preferably mounted upon an insulator block (not shown).It is contemplated that the thermocontroller unit and the soundingassembly I -be mounted upon a base plate and housed within anappropriate dust cover, although if desirable the thermocontroller canbe installed independently of the sounding mechanism. Thethermocontroller may be 'of very small size, so that the space itoccupies is inconsequential.

.Bimetallic elements 1 and 8 carry cooperating contacts 9 and Ill. Thesecontacts normally are spaced apartbut are sumciently closetogether sothat theymay engage one anotherupon warpage of. one of the elements. TheSpacing of the contacts governs, to an appreciable degree, the

promptness of response of the apparatus. In most instances satis'factoryresults are `obtained if they are spaced apartabout .001 inch, when inrepose.

The strip 'I carries, preferably wound about it; In the remainder ofthe' a resistance-coil ll. speciflcation this coil is termed the lowresistance heater. The strip I carries wound about it in similar fashiona resistance element |2 which, in the remainder of the specification, istermed the high resistance heater. Nichrome wire prefusually installedin the homes; therefore.. froxn the' manufacturing point of view,the-apparatus need only be provided with' terminals ll and li forconnection of the 'device with terminals from the transformer. v

Two-respectiveterminals o the solenoids 2 are connected together throught r e leads IB and |1 to the lead I! taken from the terminal ll. Theleads I 6 and |1 include push button switches IQ and 20. These maycorrespond respectively to the'front door and rear door push buttons ina home. i

The two other respective terminals of the solenoids 2 are connectedtogether through leads 2i and 22, to a connector 23 which is fastenedelectrically to the -bimetallic strip I of the thermocontroller. One ofthe ends of the high resistance heater |2 is also fastened electricallyto the bimetallic strip I and the otherend is likewise fastened to thebimetallic strip 1. A terminal of the low resistance heater il isfastened to the bimetallic strip 1 and the other end of this resistanceheater is connected, through lead 24, to the other terminal IS of theapparatus. If desirable, the terminal of high resistance coil may beconnected to lead 24 instead of to the bimetallic strip 1. Likewise, ifdesirable, only one eleotrostriker'unit need be employed in place of thetwo illustrated, with appropriate parallel connection to it of theswitch leads IB and |1.

In the preferred construction, assuming that the device is to beoperated on approximately 14 volts, the high resistance heater is ofapproximately 80 ohms and the low resistance heater of approximately 3.0to 6.0 ohms. Under these conditions a currentl of approximately .3ampere fiows through the circuit when the contacts I and" are separated.and the solenoids are adiusted so that they are capable of throwing thearmatures i upon a current of approximately .85 ampere, but incapable ofthrowing the armatures if the current be approximately .3 ampere orthereabouts. These values are variable'over substantial limits and theyare provided in this specification soleiy to illustrate typicalconditions.

The .operation of the circuit is as follows:

When a given one of the push buttons i! or m 2| is depressed a currentflowsv from the transformer through the push button to the solenoid withwhich it is in circuit and through the solenoid and the lead 23 to thethermocontroller. The solenoids are so connected that the deprescontrol.

Current ilowing through the lead 23 passes through the bimetalllc stripI, the high resistance heater I 2, through the bimetallic strip 1 andthrough the low resistance heater H back to the -transformer. At thistime, the contacts I and ID are separated fromone another and the valuesof the resistances are such that the total resistance in the circuit maypermit a current of approximately .3 ampere to flow, that is, a currentinsuillcient to operate the selected solenoid.

While the high resistance and low resistance coils are heated in unisonmore energy is expended in the high resistance coil and, therefore. thebimetallic strip` l is warped to a greater degree than the bimetallicstrip 1, whereupon contact is-made between the contacts 9 and i..

With contact ll being in engagement with contact 8, the high resistancecoil |2 is shunted, the

current flowing from the lead 23 through the bi-` metallic strip, thecontacts O and 1| and the low resistance heater H back to thetransformer. The current now increases to a magnitude suillcient tooperate the solenoid 2 (for instance, .85

ampere) "and, therefore, its armature is actuated to strike the bar 4and sound the signal. Meanwhile, however, the current of greatermagnitude is also fiowing through the low resistance coil and it, inturn, is being heated substantially independently of the high resistancecoil. Therefore the element 1 now warps away from the element 8 to breakthe engagement between contacts 9 and Ill.

But as soon as the contact is broken the high resistance is restorecl inthe circuit. the current drops and the high resistance coil is heatedcausing further relative movement of the bimetallic e elements andcausing consecutive contact of element ifl with element 9. Whileelementfl is short circuited it cools, andconversely, when the elementis being heated, element 1 is not being warped appreciably since theresistance of its heater is, comparatively, small. By virtue of theseconditions the elements do not move beyond a fleld of movementdetermined by the relative equilibrium which is reached through thealternate heating and cooling of them.

In the l'circuit of'Figure 3 the thermocontroller is the same asthatshown in Figure 1 and the same reference numerals are applied to thevarious parts 'of the circuit. However, a resistance 25 is connectedacross the lead 2| and the bimetallic element 1 so as to be in parallel.with the low resistance il. This arrangement presents severaladvantages. If the current required for the operation of the solenoid isin the neighborhood of approximately' ampere, (and y large to carry thecurrent without undue heating, there is difnculty in wrapping the stripbecause of the stiffness of the wire. By the installation of`a resistor2! in shunt with the low resistance heating coil ||,'the burdens imposedupon the latter are reduced and, therefore. the wire of this heaterelement may be of smaller size. The wire of smaller gauge does notstiffen the bimetallic element and, therefore. the bimetal'lic element 1responds promptly when heat is 3 sion of either vpush button effects thesame applied to it. .As a typical illustration of the electricalconditions employed in the circuit of Figure 3, the resistor 25 may beapproximately 14 ohms, the low resistance heatenapproximately ll ohmsand the high resistance heater the same as previously described.

The circuit of Figure 4 is similar to that of Figure 1 but is disclosedto show the utilization of a variable'resistance for adiusting theperiodicity to which the signal notes are sounded, so that the beat ofthe signals may be decreased or increased according to the desires ofthe user.

The circuit shown in Figure 4 comprises front and rear door sol'enoidstriker units 26 and 21 which are connected, through the leads 28 and 22to a lead 30 from the terminal |4. The leads 2| and 2| include.respectively, the front door and rear door push buttons 3| and 32. Theremaining terminals of the solenoids 28 and 21 are connectedrespectively through leads 33 and 34, to a common lead 2,5 whichincludes a variable resistance indicated generally at 18. Thisresistance is attached through lead 31 to the bimetallic element I,around which is wrapped the high resistance heater |2.. .as previouslydescribed. One of the terminala of the high resistance heater isattached to the bimetallic element 8 and the other to the'bimetallicelement 1. and a connection ll is taken from the element 1 to theterminal li.

The low resistance heater ll is carried by the bi-metalllc element 1,but one terminal of this heater is connected to the lead 29 and theother to the lead 2|.

The variable resistance 26 is'employed so that adjustments for differentsupply potentials may bemade. For a given line potential. Variation ofthe rheostat effects Variation of the time intervals between successivenotes. -As a typieal illustration of the electrical conditions whichhave been found satisfactory for this circuit. as-

- suming that the solenoids would throw their armatures when suppliedwith current of approxlmately .85 ampere and will fail to operate atapproximately .3 ampere, the low resistance heater may be of'approximately 24 ohms, the high reslstance heater may be as previouslydescribed, and the rheostat may be variable from approximately l to 'Iohms. As previously stated, these conditions are variable oversubstantially wide ranges and are provided to illustrate a typicalembodiment for the beneflt of those skilled in the art.

The operation of the circuit of Figure 4,18 'shown diagrammaticaily inFlgures 5 and 6-. As inl/Figure 5, when the front door button isdepressed the low resistance heater H is connected in series with thesolenoid winding 21 and these stitution for the push buttons shown inthe circuits of Figures 1, 3 and 4.

The holding apparatus comprises a bimetallic element 4|. carrying` aheating coil 42, one terminal of 'which is in connection with the lead4| and the other with'the bimetallic element.

. The element 4| is provided with a latch 43 and two elements in turnare connected in parallel with the winding of the solenoid 20 whichoperates to sound the front door signal.-

w, As illustrated in Figure 6, when the push button 22 at the rear dooris operated, the low reaistance'element ll is connected in series withthe windins ofthe solenoid 2|, and these in mm are connected inparallelwith the windins ot the solenoid 21 which operates the rear door nimal.

'rue push-button. mmm nie amator P18'- ure '1, is capable of holding thecircuit to'the` chime for a predetermined interval of time when the pushbutton is depressed. load: 8| and 4| with wmen this 'push button i:provided m connected in the circuit in the usual manner in subisresiliently mounted at the end opposite the latch. as upon a flexiblemember 44. A latch 45 carried on a shank 46 of the push button 41 isarranged to engage the latch 43 when the push button is depressed. Thepush button itself slides through a collar 48 which is in electricalconnection with the lead i! and the collar in t'urn is carried in aninsulating housing 49 which may be mounted to a door frame in vthe usualmanner. The shank 46 carries a washer III within the housing forengagement with a compression spring 5|.

The latch 4| is conilgurated to move past the latch 4| and then becaught by it when the push button is depressed. An electrical connectionis made through the lead 39, the collar 4|, the shanl: of the device andthe latch 43, through the heating coil 42 and the lead 40. When currentilows the heating lcoil- 42 warps the element 4| causing it to drag thelatch 48 from engagement with the latch 45 and permit the push button tobe released under the influence of the spring 5|. The interval of timerequired is dependent upon the extent of eng'agement of the latches andthe intensity'of the heat generated in the coil 42. In a typicalapparatus the push button, once depressed, may be released afterapproximately 6 or 8 seconds, during whichl time the pushy buttoncompletes the circuit to the chime apparatus so that a succession ofsignais is sounded automatically.

The thermocontroller element shown 'in Figure 8 is of a modified formand comprises a strip portion 52 and a strip portion 53 which are weldedor connected at adiacent endwise portions to form a lsubstantiallycontinuous strip element. Portion 53 carries a contact 54 whichcooperates with a contact 55. These contacts function in the same manneras the contacts land lflasshowninFlguresl and 2.

The portion", at the end opposite the contact S4, is supported in asuitable pillar or mounting member-55 and the portions 52'and 53 are soconnected that they warp in opposite directions whe they are heated,that is, the extremity of the portion 52 moving in the direction of theupper arrow and the portion 52 moving in the direction of the lower'arrow, as shown.

' The portion 52 carries the high resistance heater |2 and the portion52 the low resistance heater ll. The electrical connections to theseheater elements may be as descrlbed in connection with Flgure l orexactly the same as those shown in Figure 2 and, therefore, furtherdescription is unnecessary.

When the heater coil |2 is energized the blmetallic element' 52 iswarped upwardly and carries contact ll into ensaement with con- -tactII. Conversely, when the contact is made and heater, |.2 is shunted, theheater element il of v warps the latter element downwardly to open thecontact. 4

It will be noted from the foregoing description of all of the circuitsthat th'e arransements provide several important advantages. Thethermocontrollers are self-compensating. Variations in the temperaturesof the atmospheres surrcunding them will not change their mode orfrequency of operation. Sparking at the contacts through whichresistance is shunted is greatly reduced since the current through thecontacts is not cut off completely when the contacts are opened, butonly changes from a relatively high value to a relatively low value.Moreover, there is no difiiculty in the making of contact whether thetension be relatively strong or relatively weak.

Having described my invention, I claim:

1. A circuit interrupter comprising a high resistance thermoresponsiveelement' and a low resistance thermoresponsive element having portionsfree to move relatively in the same direction, the said resistances ofsaid thermore'sponsive elements being interconnected whereby, whenenergized in unison the high resistance thermoelement approaches the lowresistance element and the low resistance element relatively recedesfrom the high resistance element when the latter is shunted and meansfor shunting the high resistance heater comprising contacts' closed whenthe thermoresponsive elements are in predetermined relative positions,whereby the high resistance and the low resistance heaters alternatelycause said contacts to open and close.

2. An electrical circuit interrupter comprising a high resistance, a lowresistance, bimetallic elements respectively physically associated withthe high resistance and the low resistance so as to be heatedrespectively by the high resistance and the low resistance, and contactmaking means, controlled by said bimetallic elements, adapted to shuntthe high resistance from the circuit when the high resistance has causedone of the bimetallic elements to Warp to a predetermined degree.

3. An interrupter device comprising a pair of thermalresponsiveelements, mutual cooperable contact members operated by saidthermalresponsive elements, electrical resistance heaters arrange'dadjacent said thermalresponsive elements respectively for heating them,one of said resistances being arranged to exert a greater heating effectupon its thermalresponsive element than the other, the said thermalelements beingarranged to warp in the same direction when they areheated, the said contacts being arranged to shunt one of the resistanceswhen they are in engagement with one another, whereby the unshuntedresistance exerts a heating effect upon its'thermalresponsive element tomove the contacts out of engagement with one another.

LOWELL M. ALEXANDER.

